1. Field of the Invention
The present invention relates to a liquid crystal display device with a metal reflective film and, more particularly, to a structure in which, when a liquid crystal display device is manufactured by sealing a liquid crystal injection hole after a liquid crystal is injected between substrates, an operation of sealing the injection hole can be reliably performed.
2. Description of the Related Art
As shown in FIG. 7 as a conventional configuration of a liquid crystal display device, a liquid crystal display device 3 obtained by sealing a liquid crystal between a pair of substrates 1 and 2 is known. In the exemplified liquid crystal display device 3, a sealing material 4 consisting of a resin and annularly arranged along the peripheral portions of the substrates 1 and 2 is interposed between the substrates 1 and 2, and a liquid crystal is sealed in a space surrounded by the sealing material 4 and the substrates 1 and 2.
Projection portions 5 obtained by partially projecting the sealing material 4 on the center side of one end face of the substrates 1 and 2 (on the center side of the right end face in FIG. 7) toward the end face side of the substrates 1 and 2 are formed to be spaced apart from each other. These projection portions 5 are caused to reach the end faces of the substrates 1 and 2 to form a liquid crystal injection portion 6. A resin is filled in the liquid crystal injection portion 6 to form a sealed portion 7, and the liquid crystal injection portion 6 is stopped up.
When the liquid crystal display device 3 shown in FIG. 7 is of a reflection type, as shown in FIG. 8, a reflective layer 8 is formed on the rear surface side of the substrate 2.
When operations of injecting a liquid crystal and sealing the liquid crystal are performed to the reflection type liquid crystal display device 3, the operations are performed by, e.g., the procedures described below.
Pairs of substrates 1 and 2, as shown in FIG. 9, obtained in a state in which no liquid crystal is injected and before a sealed portion 7 is formed (i.e., the substrates 1 and 2 in which the injection portion 6 of the sealing material 4 is open) and a vessel 11 in which a liquid crystal 10 is saved are prepared separately from each other.
The pairs of substrates 1 and 2 are made upside down and kept above the vessel 11. This structure as a whole is put in a vacuum atmosphere such as an evacuated furnace. The pairs of substrates 1 and 2 are moved downward to dip the peripheral portions of the liquid crystal injection portions 6 of the substrates 1 and 2 into the liquid crystal 10. In this case, since a gap between each pair of substrates 1 and 2 is very small, the liquid crystal 10 can be slightly drawn into the gap between the substrates 1 and 2 from the liquid crystal injection portion 6 by capillary phenomenon.
Upon completion of this operation, when the atmosphere around the vessel 11 and the pairs of substrates 1 and 2 is returned from the vacuum atmosphere to the atmospheric atmosphere, the liquid crystal 10 can be drawn into the entire gap between the substrates 1 and 2 by using a pressure difference between the pressure in the vacuum state between the substrates 1 and 2 and the atmospheric pressure outside the substrates 1 and 2.
Upon completion of the liquid crystal drawing operation into the gaps between the pairs of substrates 1 and 2, operations of stopping up and sealing the liquid crystal injection portions 6 are performed.
The operations are performed as follows. That is, as shown in FIG. 10 of a prior art method, the pairs of substrates 1 and 2 subjected to the liquid crystal drawing operation are uprightly arrayed such that the liquid crystal injection portions 6 face the upper side. The distal end of a resin injection nozzle 12 is sequentially positioned at the openings of the liquid crystal injection portions 6 illuminated with a lighting tool 13, and a resin is injected from the distal end of the resin injection nozzle 12. A resin sticking out of each of the injection portions 6 is wiped off, and the resin of the injection portion 6 is solidified to form the sealed portion 7.
However, since the operation of injecting the resin into the liquid crystal injection portion 6 of each pair of substrates 1 and 2 by using the resin injection nozzle 12 is an important operation which may cause a liquid crystal to leak when erroneous injection such as offsetting of an injection position, the operation must be strictly performed. When the liquid crystal injection portion 6 is illuminated with the lighting tool 13, there is a problem in that the position of the liquid crystal injection portion 6 cannot be easily detected.
This problem is caused by the following reason. That is, when the substrates 1 and 2 are used in a reflection type liquid crystal display device, the reflective film 8 is formed on the entire surface of the rear surface side of the substrates 2. Because the liquid crystal injection portion 6 of another pair of substrates 1 and 2 located behind the substrate 2 in an arrangement which pairs of substrates 1 and 2 are arrayed as shown in FIG. 10, the liquid crystal injection portion 6 with the reflective layer 8 is shielded by the substrate 2 on the front side. For this reason, an operator cannot easily recognize a precise position of the liquid crystal injection portion 6. Position check must be performed by an image analyzer such as a television camera. All the positions of the liquid crystal injection portions 6 of the pairs of substrates 1 and 2 in an array state cannot be checked from the outside because each reflective layer 8 on the front side shields each liquid crystal injection portion 6 on the rear side. In addition, even if injection positions can be precisely recognized, filing of a resin may not be satisfactorily performed depending on an injection state of the resin. An amount of injection may be so excessive that the resin sticking out of the liquid crystal injection portion 6 may be adhered to the peripheral portion of the liquid crystal injection portion 6.
Uneven injection may be caused when a liquid crystal is injected into the pairs of substrates 1 and 2 as shown in FIG. 9. In a vacuum atmosphere, it is difficult to completely recognize and check whether the liquid crystal is filled into the pairs of substrates 1 and 2. Whether the liquid crystal injection process is completed is typically recognized by a time parameter of a pressure-reduction time when a vacuum atmosphere is made, and when a predetermined period of time has elapsed, completion of the injection is determined. However, if defective liquid crystal injection occurs for some reason, substrates 1 and 2 in which the defective liquid crystal injection occurs cannot be detected in the resin sealing process shown in FIG. 10. Therefore, a defective product may be manufactured.
The present invention has been made in consideration of the above circumstances, and has as its object to provide a liquid crystal display device which, when a liquid crystal injection portion is sealed and stopped up with a resin after a liquid crystal injection operation, makes it possible to easily and precisely perform the operation and makes it possible to easily detect defective liquid crystal injection.
In order to solve the above problems, the present invention provides a liquid crystal display device comprising one substrate on which a metal reflective film is formed, the other substrate arranged opposite to the substrate, a sealing material, interposed between the pair of substrates, for surrounding, together with the substrates, a liquid crystal injection space formed between the substrates, and a liquid crystal sealed into the liquid crystal injection space, characterized in that a liquid crystal injection portion is formed on the sealing material, a plurality of display electrodes are formed on a substrate surface in a region in which the liquid crystal is sealed, and, on one of the substrates, outside the display electrode forming region, an unformed region of the metal reflective film is formed on a portion including the injection portion of the sealing material.
Since the unformed region of the reflective film is formed on the portion including the injection portion of the sealing material, the position of the injection portion can be easily and reliably checked without being disturbed by the reflective film from the outside of the rear side of the reflective film. Therefore, when operations of uprightly arraying a plurality of pairs of substrates, sequentially injecting a resin into a plurality of injection portions, and stopping up the injection portions are performed, the positions of the injection portions can be checked without being disturbed by the reflective films of the other adjacent substrates. Therefore, since the positions of the injection portions can be precisely checked by the region injection portions, an operation of stopping up the injection portions can be reliably performed. In addition, even if defective injection of a liquid crystal occurs, substrates in which the detective injection occurs can be easily detected.
The metal reflective film may employ either one of a structure in which the metal reflective film is additionally formed on one substrate as an independent film and a structure in which the metal reflective film is incorporated in the substrate to be integrated. The sealing material consists of a resin, and is formed on the opposite surface sides of the substrates by a method such as printing. The unformed region of the metal reflective film can be formed at an arbitrary position by the following manner. That is, the metal reflective film is formed by a film forming method after a resist is formed on a substrate, and the resist is peeled from the substrate.
The present invention provides a liquid crystal display device characterized in that, on one substrate, on which a metal reflective film is formed, of a pair of substrates which hold a liquid crystal therebetween, drawn electrodes of the display electrodes are formed at the edges of the substrates outside a region in which a plurality of display electrodes are formed on substrate surfaces in a region which holds the liquid crystal therebetween, and an unformed portion of the metal reflective film is formed in the drawn electrode forming region.
When the unformed portion of the metal reflective film is formed in the region in which the drawn electrodes are formed, the drawn electrodes can be easily and reliably formed without being disturbed by the metal reflective film, and the terminals of a drive IC or the like can be easily and reliably connected. In addition, since the positions of terminal connection portions can be checked without being disturbed by the metal reflective film, connection of the terminal connection portions can be easily checked without being shielded by the reflective film.
The present invention further provides a liquid crystal display device comprising one substrate on which a metal reflective film is formed, the other substrate arranged opposite to the substrate, a sealing material, interposed between the pair of substrates, for surrounding, together with the substrates, a liquid crystal injection space formed between the substrates, and a liquid crystal sealed in the liquid crystal injection space, characterized in that a liquid crystal injection portion is formed on the sealing material, a plurality of display electrodes are formed on a substrate surface in a region in which the liquid crystal is sealed, a first drawn electrode for a display electrode for one of the substrates and a second drawn electrode for a display electrode of the other of the substrates are formed at the edge of one of the substrates, electrode connection means is arranged on the sealing means, the second drawn electrode and the display electrode of the other of the substrates are connected to each other by the electrode connection means, and an unformed portion of the metal reflective film is formed in a region in which the second drawn electrode and the display electrode of the other of the substrates are connected to each other on the sealing material.
In the structure in which the second drawn electrode of one of the substrates is connected to the display electrode of the other of the substrates through the electrode connection means of the sealing material, since no metal reflective film is formed on the connection portion between these electrodes, the drawn electrodes can be easily formed or connected, and the drawn electrode portion can be easily checked without being shielded by the metal reflective film.
The liquid crystal display device may have a configuration characterized in that, on one of the substrates, outside the display electrode forming region, an unformed region of the metal reflective film is formed on a portion including the injection portion of the sealing material.
Since the unformed region of the reflective film is formed on the portion including the injection portion of the sealing material, the position of the injection portion can be easily checked from the outside. Therefore, when operations of uprightly arraying a large number of substrates, sequentially injecting a resin into a large number of injection portions, and stopping up the injection portions is performed, the positions of the injection portions can be easily seen without being disturbed by the reflective films of the other adjacent substrates. For this reason, the operation of stopping up the injection portion by injection of a resin can be easily and reliably performed.
The liquid crystal display device may have a configuration characterized in that, on one of the substrates, outside the display element forming region, an unformed portion of the metal reflective film is formed in the drawn electrode forming region.
The electrode connection means arranged on the sealing material preferably consists of conductive particles added to the region constituting the sealing material.
If a sealing material has a configuration in which conductive particles are diffused in a resin, when one substrate and the other substrate are brought into airtight contact with each other to sandwich the sealing material, an electrode formed on one substrate and an electrode formed on the other substrate are connected through the conductive particles of the sealing material. Of the conductive particles of the sealing material, conductive particles sandwiched by the electrodes of a pair of substrates, i.e., conductive particles existing in the direction of the substrate thickness, are sandwiched by the electrodes of the pair of substrates to be in contact with these electrodes, so that these electrodes are electrically connected to each other. However, the conductive particles existing in the direction of the substrate surface are spaced apart from each other. For this reason, electrodes adjacent to each other in the direction of the substrate surface are not short-circuited. Therefore, electrodes adjacent to each other on the same substrate are not short-circuited, and only electrodes which are opposite to each other and must be connected to each other can be reliably connected to each other.
In addition, since a structure having the metal reflective film is incorporated includes the structure in which the conductive particles diffused in the sealing material are sandwiched by the opposing substrates, when the conductive particles are pressed on both the substrates, the conductive particles may break through laminate films formed on portions of the sealing material which are in contact with the substrates. In this case, in a structure in which connection is made on a drawn electrode connection portion by the conductive particles in the sealing material, if a metal reflective film exists on the connection portion, the conductive particles may reach the metal reflective film to short-circuit the drawn electrode to the metal reflective film. However, such a short circuit can be prevented from being made by forming the unformed region of the metal reflective film on the drawn electrode connection portion.